JP5538925B2 - Image processing apparatus and image processing method - Google Patents

Description

The present invention relates to an image processing apparatus and an image processing method for performing image correction.

  If the printer is continuously used, the output characteristics such as color and gradation of the output of the printer fluctuate due to changes over time in ink density and ink ejection characteristics of the head. A technique called calibration has been developed to stabilize output characteristics regardless of changes over time. By periodically measuring the output characteristic amount, calculating calibration information from the measured value, and correcting based on that information, the printer can be used with the output characteristic kept stable. In order to periodically calculate calibration information, it is also conceivable to store the calculated calibration information and switch to past information as necessary (Patent Document 1).

  Conventionally, there are only CMYK inks such as cyan (C) / magenta (M) / yellow (Y) / black (K) / light cyan (LC) / light magenta (Lm) ink. However, in order to improve the image quality of the printer, inks called special color inks such as gray (Gr) / red (R) / green (G) / blue (B) ink are also used, and the number of colors is increased to about 8 to 12 colors. Is progressing. Furthermore, considering the difference in surface ink absorption between glossy paper and non-glossy paper, in order to obtain better output, the ink for glossy paper and the ink for non-glossy paper are used even for the same color ink. Sometimes used. The number of inks used may differ depending on whether printing is performed with emphasis on image quality or printing with emphasis on printing speed. For example, when high-quality printing is performed, printing is performed with a larger number of inks using special color ink or the like.

JP 2000-301773 A

  After the calibration information is created, color misregistration occurs due to variations in ink density and head ejection amount over time. Therefore, it is desirable to periodically create calibration information. Conventionally, the creation of calibration information has been performed for all installed inks at the same time, and therefore, information on all inks is regularly updated. However, depending on the quality of the printer and the increase in color, the inks that can be used differ depending on the paper and quality, and all the inks may not be used on one paper. In that case, calibration information for all inks cannot be created at one time.

  When printing on paper that uses ink other than the one for which calibration information was calculated last time, if the calibration information is always calculated immediately before printing, the information on the ink to be used is the latest, so the same accuracy as normal Is obtained. However, calculation of calibration information takes time and is troublesome for the user, which is not desirable.

  When printing on paper that uses ink other than the ink for which calibration information was calculated last time, calibration information in which all inks used for the paper to be printed are calculated from the history calculated in the past other than the previous time. Then, it is conceivable to use the calibration information of the history. However, in this case, all the inks use the calibration information at the time of this history, and since newer information may be used depending on the type of ink, it cannot be used effectively.

  In addition, the number of inks is increasing and the number of ink types is increasing, but the effect on the visual characteristics on the calibration differs for each ink. If some calibration information of chromatic inks such as cyan (C) / magenta (M) / yellow (Y) / light cyan (Lc) / light magenta (Lm) ink is shifted, the color balance is Collapse. Sometimes it becomes noticeable in gray or skin color, which has high sensitivity in visual characteristics. On the other hand, when the calibration information of achromatic ink such as black (K) or gray (Gr) is shifted, it affects only the lightness component and does not affect the color balance. In addition, in the case of special color inks such as red (R) / green (G) / blue (B), the special color is not used for the gray axis, but is used only in a specific color gamut. Not give. In other words, if the color balance of chromatic ink is shifted, it becomes prominent in gray and skin color, which have high sensitivity in visual characteristics, and image degradation is likely to occur. On the other hand, since the deviation of the lightness component is allowed more than the deviation of the color balance, it can be said that the deviation of the achromatic ink has a small influence on the visual characteristics. Further, since the shift of the special color ink affects only a specific color gamut, it can be said that the influence on the visual characteristics is small.

  In this way, it is necessary to consider a calibration method in consideration of the fact that the influence on the visual characteristics on the calibration differs for each ink. If calibration information for all inks cannot be calculated at the same time, it is possible to realize a calibration method that maintains calibration accuracy so that deviations in the color balance of chromatic ink that has the greatest impact on visual characteristics can be tolerated. is necessary.

An object of the present invention is to solve such conventional problems. The present invention provides an image processing apparatus and an image processing method capable of maintaining calibration accuracy so that a deviation in color balance can be allowed when calibration information is not acquired for the ink used for printing at the same time. The purpose is to do. It is another object of the present invention to provide an image processing apparatus and an image processing method that can reduce the number of steps of the user when performing calibration.

To solve the above problems, an image processing apparatus according to the present invention, the first ink, the image processing for recording an image on the second ink and third ink recording medium using the discharge recording head capable of a an apparatus, said first ink and said second ink first measurement result based rather the first ink and the second ink each density correction patch recorded in time with Information is stored and based on the measurement result of the patch recorded at a second time after the first time using the second ink and the third ink without using the first ink Storage means for storing density correction information of the second ink and the third ink, and a third time after the second time using the first ink and the second ink for recording the image, the first Using the concentration correction information of the first ink based on the measurement results of the patch recorded in time, and a density correction information of the second ink based on the measurement results of the patch stored in the second time Correction means for correcting image data of the image.

  According to the present invention, when the calibration information is not acquired for the ink used for printing at the same time, the calibration accuracy is maintained so that the deviation of the color balance having the greatest influence on the visual characteristics can be allowed, and the user The number of man-hours can be reduced.

It is a figure which shows an example of a structure of an image correction system. It is a flowchart which shows the procedure of the image processing of printing in a normal RGB printer. It is a figure which shows the relationship between a paper and use ink. It is a flowchart which shows the procedure of the process which calculates calibration information. It is a flowchart which shows the procedure of the process which correct | amends an output using the calculated calibration information. FIG. 6 is a diagram illustrating rank values of inks used for paper A and paper D, respectively. 6 is a diagram illustrating an example of combining ink rank values used for paper A and paper D, respectively. FIG. FIG. 6 is a diagram illustrating rank values of ink used for each of paper A and paper B. 6 is a diagram illustrating an example of combining ink rank values used for paper A and paper B, respectively. FIG. FIG. 6 is a diagram illustrating rank values of inks used for paper A and paper C, respectively. 6 is a diagram illustrating an example of combining ink rank values used for paper A and paper C, respectively. FIG. FIG. 4 is a diagram illustrating inks used for paper A and paper E, respectively. FIG. 6 is a diagram illustrating rank values of inks used for paper A and paper E, respectively. 6 is a diagram illustrating an example of combining ink rank values used for paper A and paper E, respectively. FIG. It is a figure which shows a response | compatibility with a colorimetric value and ink discharge amount.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the present invention according to the claims, and all combinations of features described in the present embodiments are not necessarily essential to the solution means of the present invention. . The same constituent elements are denoted by the same reference numerals, and the description thereof is omitted.

[First embodiment]
FIG. 1 is a diagram illustrating an example of the configuration of an image correction system. The information processing apparatus 100 includes a video card 104 to which a CPU 101, a ROM 102, a RAM 103, and a monitor 114 (which may include a touch panel) are connected. Further, a storage unit 105 such as a hard disk drive or a memory card is provided as a storage area. In addition, a serial bus interface 108 such as USB or IEEE 1394 for connecting a pointing device 106 such as a mouse, stylus and tablet, a keyboard 107 and the like is provided. Further, a network interface card (NIC) 116 connected to the network 115 is provided. These components are connected to each other via a system bus 109. In addition, a printer 110 such as an ink jet printer as an image forming apparatus, a digital camera 111, a colorimeter 112, a scanner 113, and the like can be connected to the interface 108.

  The CPU 101 loads a program (including an image processing program described below) stored in the ROM 102 or the storage unit 105 into the RAM 103 that is a work memory, and executes the program. After that, by controlling each of the above components via the system bus 109 according to the program, the function of the program is realized.

  FIG. 1 shows a general configuration of hardware of the information processing apparatus described in this embodiment, and even if a part of the configuration is missing or another device is added, it is included in the scope of the present invention. It is. In this embodiment, a configuration will be described in which correction is performed by performing printing and colorimetry one tone for each ink on a certain recording medium (paper or the like) among a plurality of types of recording media.

  FIG. 2 is a flowchart showing the procedure of image processing for printing in a normal RGB printer. First, in S201, data such as image data and document data to be printed is converted using a color correction table. Color gamut compression from the color space of the input data to the color space of the printer and color processing such as memory colors are performed. Here, conversion from the input color space to the device RGB color space of the printer by a three-dimensional LUT is common. In step S202, the color separation table is used to separate the ink component signal values such as CMYK. Here, conversion from the device RGB color space of the printer to the ink color of the printer by a multi-dimensional LUT from three dimensions to n dimensions is common. In step S203, tone correction is performed on the signal values of ink components such as CMYK using a one-dimensional LUT called a tone correction table. Finally, in S204, the signal is converted into an ink dot signal by error diffusion or dithering by quantization conversion, sent to the printer as print data, and printed.

  FIG. 3 is a diagram illustrating a relationship between a recording medium such as a sheet and usable ink in this embodiment. In this embodiment, the cyan ink (C1 / C2), the magenta ink (M1 / M2), and the black ink (K1 / K2) have two types of inks with different characteristics, and the yellow ink (Y1) has only one type. Have ink. Inks to be used are determined corresponding to a plurality of types of paper, and an optimum combination is made in consideration of the characteristics of each ink and the characteristics of the paper. Circles in the figure indicate the ink used on the paper. Paper A uses C1, M1, Y1, and K1, Paper B uses C2, M2, Y1, and K1, Paper C uses C1, M1, Y1, and K2, and Paper D uses C1, M1, and so on. , Y1, and K1 are used for printing.

  Next, the calibration technique will be described. First, the principle of calibration will be described. If the printer continues to be used, output characteristics such as color and gradation of the output of the printer fluctuate due to changes over time in ink density and ink ejection characteristics of the head. Even in the same ink tank due to a phenomenon such as sedimentation of the evaporating colorant, the ink density changes over time. In this embodiment, the ink ejection characteristics of the head indicate the amount of ink ejected from one nozzle (ink ejection amount). In general, weight and volume are used as the ink amount, but in this embodiment, description will be made using weight (ng).

  The ink discharge amount is determined mainly by the head characteristics such as the nozzle diameter and voltage of the head, and varies depending on the change with time in addition to the variation at the time of manufacture. Further, since the structure of the head and the viscosity of the ink are different for each ink, the ink discharge amount is also different. Here, a certain discharge amount is defined as a reference discharge amount. In this embodiment, the reference discharge amount is set as the discharge amount that becomes the center of the variation in the manufacturing process difference, and 3 ng is set as the reference discharge amount. A discharge amount rank value for calibration (hereinafter, simply referred to as a rank value) is defined based on the reference discharge amount. The reference discharge amount is set to rank value = 0, and when the deviation from the reference discharge amount is small, a negative value is set, and when it is large, a positive value is set. In this embodiment, it is assumed that the rank value changes by 1 when there is a deviation of 0.1 ng. For example, when the discharge amount is 2.6 ng, the rank value = −4.

  When the ink discharge amount is large, the print result is output darkly, and when the ink discharge amount is small, the print result is output lightly. If the ink discharge amount is known, heads with different ink discharge amounts can be corrected so that output characteristics such as output color and gradation are the same. For example, when the rank value is +3, since the discharge amount is 3.3 ng, the ink is applied to the paper by 10% more than the reference discharge amount. When the conversion is performed using the gradation correction table in S203, a gradation correction table is created so as to be 10% less than the gradation correction table for the reference ejection amount, and correction is performed using the table. As a result, the same output characteristics as the reference ejection amount can be realized in a printer having an ink ejection amount of rank value = + 3.

  Alternatively, a printer with rank value = + 3 may be actually prepared, and the gradation correction table may be actually created so that the output characteristics in the case of the reference ejection amount match. A gradation correction table is created in advance so that the output characteristics are the same as the reference discharge amount for all rank values. If the rank value is known for each ink, correction is performed using a gradation correction table created in advance according to the rank value, so that the same output characteristics can be obtained regardless of the ejection amount for each ink. be able to.

  FIG. 15 is a diagram illustrating an example in which a relationship between an ink discharge amount and an output colorimetric value in a certain ink is plotted by outputting with a printer having a different ink discharge amount. As shown in the figure, it can be seen that there is a correlation between the ink discharge amount and the output color. That is, when the output color (colorimetric value) is examined for each ink color, the ink ejection amount or rank value of the ink associated with each output color can be estimated. Actually, the ink discharge amount is estimated in a state including not only the difference in the ink discharge amount due to the nozzle diameter and the like, but also the change in the output color due to the change in the ink density. However, by changing the gradation correction table according to the estimated ejection amount or rank value, fluctuations due to changes in ink density are also appropriately corrected simultaneously. The ink discharge amount or rank value thus estimated does not depend on the paper, but depends only on the printer head and ink density. In this embodiment, information related to the ink ejection amount or rank value is referred to as calibration information (density correction information).

  Next, a processing flow in calibration will be described. When the user actually performs calibration, it is roughly divided into two operations. Calibration information is acquired, and output is corrected using the acquired calibration information and printed. The step of acquiring the calibration information is periodically performed in order to grasp the fluctuation of the output characteristics with the passage of time. In addition, when there is a possibility that the output characteristics may fluctuate greatly, such as when the head or ink is replaced, this is performed separately.

  The process of acquiring calibration information will be described in detail with reference to FIG. First, in S401, the user designates a sheet to be used for obtaining calibration information. In step S402, a patch is printed using patch data for obtaining calibration information. In step S403, color measurement of the printed patch is performed. Calibration information is acquired from the colorimetric values obtained in S404. In step S405, the acquired calibration information is stored.

  In step S401, the user designates a sheet on which a patch necessary for acquiring calibration information is printed. After this, the paper used for actually printing the data may be used, or another paper at hand may be used. In S402, in order to acquire the ink discharge amount for each ink, a single-color patch is printed. Since the usable ink differs depending on the paper, only the ink that can be used in accordance with the paper designated in S401 is printed. In S403, the colorimetric value of the printed patch is acquired. Colorimetry is performed using a colorimeter, but colorimetric values may be obtained simply using a scanner, camera, or the like, or RGB values may be used as they are.

  In S404, calibration information is acquired from the colorimetric values. As shown in FIG. 15, there is a correlation between the ink discharge amount and the colorimetric value. For this purpose, colorimetric values for each ink discharge amount are obtained in advance and stored in a list format, and the measured colorimetric values are compared with the stored colorimetric values to support the closest colorimetric value. The ink discharge amount to be performed can be estimated as the current ink discharge amount of the printer. The acquired ink discharge amount is used as printer calibration information at time A when the patch is printed (discharge amount acquisition).

  The relationship between the ink discharge amount and the colorimetric value stored in advance may be stored in a lookup table and the closest colorimetric value may be acquired by referring to the LUT. As another method, the relationship between the ink discharge amount and the colorimetric value may be approximated by a linear expression, and the linear expression may be stored and calculated from the linear expression. In order to increase the accuracy of the relationship, approximation may be performed using a high-order expression instead of a linear expression. In addition, even if the same amount of ink is ejected, the color development characteristics differ for each paper, so it is necessary to obtain and hold colorimetric values for each ink ejection amount in advance for each paper. At this time, in the case of printers in the same state, the relationship between the ink ejection amount and the colorimetric values is defined so that the same value of calibration information can be obtained even if acquired on different sheets.

  In step S405, the acquired calibration information is stored. The information to be acquired includes the calibration information, the time when the calibration information is acquired, and the paper used for the acquisition. Each time calibration information is acquired, the information is accumulated and stored in a memory or the like. Here, as acquisition of calibration information, in order to improve estimation accuracy, a plurality of patches having different densities may be printed to acquire the ink discharge amount.

  Next, processing for performing density correction using the acquired calibration information and printing in the present embodiment will be described in detail with reference to FIG. In addition to the normal printing flow described with reference to FIG. 2, the tone correction table is switched using the acquired calibration information. First, in S501, the paper and print quality used for printing set by the user are received. S502 is a first reading step of reading the latest time when the calibration information is acquired for each ink associated with the designated sheet from a plurality of stored calibration information. S503 is a determination step of determining whether the acquisition time of the calibration information of the chromatic color ink among the inks used for the designated paper is the same time. As will be described later, the chromatic ink is, for example, cyan (C), magenta (M), and yellow (Y) ink. In these chromatic color inks, when the latest time when the calibration information is acquired is the same time, the information of this time can be used, so the process proceeds to S505. If it is not the same time, a second reading step of reading the time when the calibration information of the chromatic color ink is simultaneously acquired from the time when the previous calibration information stored in the above-described memory or the like is acquired in S504. Then, the process proceeds to S505. In S505, calibration information (for example, rank value) of chromatic ink acquired at the same time is determined, and in S506, an optimum gradation correction table is selected based on this calibration information (first correction step). ).

  In S507, the data is color-converted using the color correction table. In step S508, the color separation table is used to convert the ink component signal value. In step S509, conversion is performed using the gradation correction table selected in step S506. Finally, in S510, the data is converted into an ink dot signal by an error diffusion method or a dither method by quantization conversion, sent to a printer as print data, and printed. By switching to the optimum gradation correction table according to the calibration information thus determined, printing can be performed with optimum output characteristics.

  Here, in the present embodiment, the latest ink is used regardless of the time difference from the chromatic color ink, such as black ink which is an ink other than the chromatic color. When using the latest one, the time may be different from that of the chromatic color ink. In S506, an optimum gradation correction table is prepared for each rank value in advance for all rank values, and the gradation correction table corresponding to the rank value determined in S505 is selected.

  In the present embodiment, the inks that can be used for the paper A, the paper B, the paper C, and the paper D are different as described above. Next, a description will be given of the control and effect of calibration by combining each sheet. As shown in FIG. 3, the paper A uses C1, M1, Y1, and K1, the paper B uses C2, M2, Y1, and K1, the paper C uses C1, M1, Y1, and K2, On the paper D, printing is performed using C1, M1, Y1, and K1. Ink is used properly according to the paper in an optimal combination in consideration of the characteristics of each ink and the paper.

  The ink that can be used differs depending on the paper and the quality, and all the inks cannot be used on one paper. Therefore, the calibration information of all the inks cannot be acquired at the same time. It is troublesome for the user to acquire the calibration information for the necessary ink every time. Considering the effort of the user, it is necessary to realize calibration with little influence on visual characteristics by combining calibration information obtained at different times.

  The following can be said in terms of visual characteristics. Near-gray and flesh-color reproduction is more sensitive to human visual characteristics than high-saturation color reproduction. For this reason, as the accuracy required for calibration, color reproduction near gray or skin color, that is, color balance is important. In addition, by suppressing the color balance shift as much as possible so that the color gamut having a large shift is reduced, calibration with less influence on the visual characteristics is realized.

  When the calibration information at different times is used, there is a case where the calibration information of the specific ink is shifted. The influence when the calibration information is shifted only for specific ink will be described. When some of chromatic colors such as cyan (C) / magenta (M) / yellow (Y) / light cyan (Lc) / light magenta (Lm) ink are shifted, the color balance is lost. Sometimes it becomes prominent near gray or skin color, which is highly sensitive in terms of visual characteristics, and such a shift is undesirable. It can be said that the shift of the chromatic color ink has a great influence on the visual characteristics. On the other hand, when an achromatic ink such as black (K) or gray (Gr) is shifted, it affects only the lightness component and does not affect the color balance. Since the deviation of the brightness component is allowed more than the deviation of the color balance, it can be said that the deviation of the achromatic ink has a small influence on the visual characteristics. Further, regarding spot color inks such as red (R) / green (G) / blue (B), a case where a spot color is not used for the gray axis or a case where the spot color is used only in a specific color gamut is considered. In this case, only a specific color gamut is shifted without affecting the skin color or gray, and it can be said that the shift of the special color ink has a small effect on the visual characteristics.

  The actual combination of sheets will be described. First, the combination of paper A and paper D will be described with reference to FIGS. As shown in FIG. 6, the ink used for paper A and paper D is the same for the two papers C1, M1, Y1, and K1. First, at time 1, a rank value is acquired using the paper D. After a certain period of time, the rank value is acquired using paper A at time 2. Numerical values in the figure represent rank values.

  In time 1 and time 2, the inks for which rank values have been acquired are the same ink, and the difference between the two is due to fluctuations in the ink ejection amount including the ink density over time. What is close to the latest ink discharge amount is calibration information based on the new time 2.

  After that, consider a case where printing is performed on paper A at time 3 which is not much different from time 2. It is obvious that the optimum result can be obtained by using the calibration information performed at time 2. On the other hand, let us consider a case where printing is performed on paper D at time 4 which is not much different from time 2. In this case, since the calibration information of the inks C1, M1, Y1, and K1 used on the paper D is acquired at time 2, an optimum result can be obtained by using the result acquired at time 2. .

  Next, a combination of paper A and paper B will be described with reference to FIGS. Paper A and paper B use the same ink for Y1 and K1, but C1, M1, C2, and M2 are inks that are not used in common. First, at time 1, a rank is acquired using the paper B. After a certain period of time, the rank is acquired using paper A at time 2. After that, consider a case where printing is performed on paper A at time 3 which is not much different from time 2. It is obvious that the optimum result can be obtained by using the calibration information performed at time 2. On the other hand, let us consider a case where printing is performed on paper B at time 4 which is not much different from time 2. Among the inks C2, M2, Y1, and K1 used on the paper B, the latest calibration information is Y1 and K1 information at time 2, and C2 and M2 are information at time 1. When the latest information is used, only Y1 of the chromatic colors C2, M2, and Y1 has a different acquisition time.

  Here, the change with time of the ink discharge amount will be described. Normally, when a plurality of colors of ink are used in the same usage situation, the change in ink discharge amount with the passage of time changes in the same way, so that the color balance is maintained. However, if the usage status of the ink is different, the change with time becomes larger as the ink is used more frequently, so that the color balance is lost as time passes.

  When the latest rank value of each ink is used at time 4 described above, the rank value at time 1 is used for C2 and M2, and the rank value at time 2 is used for Y1, as shown in FIG. As shown in FIG. 8, the rank value of time 2 which is the latest information of Y1 ink is smaller than the rank value of time 1. For this reason, at time 4, when the calibration information at time 2 is used for Y1, less Y1 ink is ejected than when the calibration information at time 1 is used. Then, the color balance with the C2 and M2 inks using the calibration information of time 1 is lost. Therefore, when printing on paper B at time 4, the color balance is maintained by reading and using the calibration information of time 1 in which the rank values of the chromatic inks C2, M2, and Y1 are acquired at the same time. The image can be printed. On the other hand, K1 is an influence on the lightness component, and the use of new calibration information approaches the lightness desired to be output, so the information of time 2 that is the latest information is used.

  As described above, when different chromatic color inks are used for each paper, the time for obtaining calibration information for each ink may not be the same. At this time, if the latest calibration information is used for each ink, the color balance is lost. On the other hand, in the present embodiment, calibration information obtained by acquiring chromatic color ink at the same time is used (second correction step). As a result, printing can be performed while maintaining the color balance.

  Next, the combination of the paper A and the paper C will be described with reference to FIGS. Paper A and paper C use the same ink as C1, M1, and Y1, but K1 and K2 are inks that are not used in common. First, at time 1, a rank is acquired using the paper C. After a certain time has elapsed, at time 2, the rank is acquired using the paper A. After that, consider a case where printing is performed on paper A at time 3 which is not much different from time 2. It is obvious that the optimum result can be obtained by using the calibration information performed at time 2. On the other hand, let us consider a case where printing is performed on paper C at time 4 which is not so different from time 2. Among the inks C1, M1, Y1, and K2 used on the paper C, the latest calibration information is information on time 2 for C1, M1, and Y1, and information on time 1 only for K2. The latest information of C1, M1, and Y1 that are chromatic color inks is acquired at the same time, and is output with correct output characteristics, and the color balance is maintained. On the other hand, since the K2 ink is information a little before, the change from the acquisition time affects the deviation of the brightness component. However, since the influence of the visual characteristics on the brightness component is smaller than the color balance, the information acquired at time 1 is used as it is. In this case, since the deviation from the original output characteristic is only the brightness component, it is used as an acceptable calibration effect.

  As described above, by selecting calibration information to be used for each ink from a plurality of calibration information acquired at different times, it is possible to realize an acceptable calibration effect without generating user's trouble each time. . In addition, chromatic color ink uses calibration information performed at the same time, and other inks can use calibration information performed at different times. Can be realized.

[Second Embodiment]
As a second embodiment, a case where the relationship between the paper and the ink used is different from that in the first embodiment will be described. FIG. 12 shows the relationship between the paper and the ink used in this embodiment. Circles in the figure indicate the ink used on the paper. In this embodiment, cyan ink (C1), magenta ink (M1), yellow ink (Y1), and black ink (K1) are used on both papers, and red ink (R) and green ink (G) are It is used only on paper B. For paper A, printing is performed using C1, M1, Y1, and K1, and for paper B, printing is performed using C1, M1, Y1, K1, K1, R, and G. The R and G inks are not used in the gray axis or flesh color gamut, but have characteristics that are used only in the red and green high chroma gamuts.

  Next, a combination of paper A and paper E will be described with reference to FIGS. The inks used for the paper A and the paper E are the same as those for C1, M1, Y1, and K1, but R and G are inks that are used only for the paper B. First, at time 1, the rank is acquired using the paper E. After a certain time has elapsed, at time 2, the rank is acquired using the paper A. After that, consider the case where printing is performed on paper A at time 3 which is not much different from time 2. It is obvious that the optimum result can be obtained by using the calibration information performed at time 2. On the other hand, let us consider a case where printing is performed on paper E at time 4 which is not much different from time 2. Of the inks C1, M1, Y1, K1, R, and G used on the paper E, the latest calibration information is information on time 2 for C1, M1, Y1, and K1, and information on time 1 for R and G. It becomes. The latest information on the chromatic inks C1, M1, and Y1 is acquired at the same time, and is output with the correct output characteristics, and the color balance is maintained. Since K1 ink is also the latest information, it is output with correct output characteristics. However, since the R and G inks are information a little before, there is a deviation due to fluctuations from the acquisition time, but they are not used on the gray axis or skin color, but are used only in the high saturation color gamut of red and green. Only affects certain color gamuts. Since it is used only in a specific color gamut, the effect of visual characteristics is small compared to color balance. Therefore, the information acquired at time 1 is used as it is. In this case, since the possibility of deviation from the original output characteristic is only a specific color gamut, it is used as an acceptable calibration effect.

  As described above, by selecting calibration information to be used for each ink from a plurality of calibration information acquired at different times, it is possible to realize an acceptable calibration effect without generating user's trouble each time. . Furthermore, the chromatic color ink excluding the special color ink can be calibrated with the color balance being suppressed as much as possible by using the calibration information performed at the same time. Further, as in the present embodiment, when chromatic color inks other than special color inks are always acquired at the same time regardless of the paper, the latest calibration information is always acquired in S505. Also good.

[Third embodiment]
In the first and second embodiments, the description has been made on the assumption that the calibration information of the chromatic color ink satisfying the condition for the ink used for each sheet is in the history. However, there is not always calibration information that satisfies the conditions. Although it was in the history, it is considered that the correction effect is not sufficiently obtained even if it is older than a predetermined time and used as calibration information. An example in that case will be described.

  The process of acquiring calibration information is as described in the first embodiment. A process of performing output correction using the acquired calibration information and printing will be described. First, in S501, the user specifies the paper and print quality used for printing. Next, in S502, the latest time when the calibration information is acquired for each ink is read in accordance with the sheet designated from the stored plurality of calibration information. Then, it is determined whether the acquisition time of the calibration information of the chromatic color ink is the same time among the inks used in the paper / print quality specified in S503. If it is the same time, the same processing as in the first embodiment is performed. If it is not the same time, the calibration information is determined by searching for the same time from the past acquisition times in the first embodiment, but in this embodiment, a message indicating that a correct calibration result cannot be obtained. To the user. Alternatively, the user is notified again of a message that calibration information needs to be acquired. If the user stops printing after receiving the message, the printing ends. On the other hand, when the user receives the message but continues printing, the printing is continued using the calibration information held as the initial value. Also, if the chromatic color of the ink used is acquired at the same time, the difference time between the current time and the acquisition time is obtained, and if it is old information that has passed a predetermined time, Similarly, a message may be displayed. If printing is to be continued after the display, printing is continued using the calibration information as it is.

  In this way, even when a sufficient calibration effect cannot be obtained, displaying a message to the user makes it possible for the user to determine whether to perform printing. Here, if necessary, calibration information can be acquired again to obtain a sufficient calibration effect.

  As described above, the ink that can be used differs depending on the paper and the quality, and the calibration information performed at different times for each ink can be used to perform calibration with reduced user effort. Furthermore, because chromatic ink uses calibration information performed at the same time, color balance deviation that is easily perceived by human visual characteristics can be minimized, and fluctuations in printer output characteristics due to changes over time, etc. Calibration with reduced noise can be realized.

  In addition, compared to the deviation of brightness or the specific color gamut, which has a large tolerance range in human visual characteristics, color balance deviation (especially in the vicinity of gray and skin color) that is easily perceived by human visual characteristics is suppressed as much as possible. Calibration that suppresses fluctuations in output characteristics due to changes or the like can be realized.

  In addition, when there is no calibration information that can allow the color balance deviation or when the information is older than a predetermined time, printing is performed with a color balance deviation by warning the user or prompting calibration again. Can be prevented.

[Other Examples]
In the above embodiment, the ink system uses cyan, magenta, and yellow as the chromatic color ink. However, the configuration of the ink system is not limited to this, and light cyan ink, light magenta ink, and light yellow ink are used. It may be an ink system.

  The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

  The present invention can also be applied to the case where the program is distributed to a requester via a communication line such as personal computer communication from a storage medium that records the program code of software that implements the functions of the above-described embodiments. Needless to say.

  Note that the present invention can also be applied to a system including a plurality of devices (for example, a personal computer, an interface device, a scanner, a printer, and a colorimeter). Further, the present invention may be applied to an apparatus in which these are combined (for example, a color copying machine, a color / facsimile apparatus, and a multifunction machine).

Claims (14)

An image processing apparatus for recording an image on a recording medium using a recording head capable of discharging a first ink, a second ink, and a third ink ,
Storing the first ink and the second ink first based rather the the measurement results of the patch recorded on the time the first ink and the second ink each density correction information using, The second ink based on the measurement result of the patch recorded at a second time after the first time using the second ink and the third ink without using the first ink. Storage means for storing density correction information of the third ink ;
In order to record the image at a third time after the second time using the first ink and the second ink, the measurement result of the patch recorded at the first time said density correction information of the first ink-based, using a density correction information of the second ink based on the measurement results of the patch stored in the second time, correcting the image data of the image Correction means;
An image processing apparatus comprising: The image processing apparatus according to claim 1, wherein the storage unit stores the density correction information for each time when a patch is recorded and for each ink . Said density correction information, the image processing apparatus according to claim 1 or 2, characterized in that the information indicating the rank of the obtained ink discharge amount based on the colorimetric values of patches. The image processing apparatus according to claim 3 , wherein the correcting unit corrects the image data using a correction table corresponding to the rank . The types of the first ink and the second ink recording medium the patch is recorded in the first time using the, the first and the second without the ink ink and the third ink image processing apparatus according to any one of claims 1 to 4, characterized and Turkey different from the type of recording medium the patch is recorded in the second time using a. Wherein the first ink and the third ink are achromatic inks, the image processing apparatus according to any one of claims 1 to 5 wherein the second ink is characterized in that it is a chromatic color ink . The image processing apparatus according to claim 6, wherein the first ink and the third ink are black inks having different characteristics. The image processing apparatus according to any one of claims 1 to 7, further comprising a recording means for recording the image using the recording head based on the image data corrected by said correction means . The recording head according to any one of claims 1 to 8, wherein the recording head ejects either the first ink or the third ink according to a type of the selected recording medium. The image processing apparatus described. An image processing method for recording an image on a recording medium using a recording head capable of discharging a first ink, a second ink, and a third ink ,
Said first ink and said second ink first based rather the the measurement results of the patch recorded on the time the first ink and the second ink each concentration correction information storage means using Memorizing the process,
The second ink based on the measurement result of the patch recorded at a second time after the first time using the second ink and the third ink without using the first ink. and as factories to be stored in and the third ink the storage means the density correction information,
In order to record the image at a third time after the second time using the first ink and the second ink, the measurement result of the patch recorded at the first time said density correction information of the first ink-based, using a density correction information of the second ink based on the measurement results of the patch stored in the second time, to correct the image data of the image and as that engineering,
An image processing method comprising: The image processing method according to claim 10, wherein the density correction information is information indicating a rank of an ink discharge amount acquired based on a colorimetric value of a patch. The types of recording media on which patches are recorded at the first time using the first ink and the second ink are the second ink and the third ink without using the first ink. The image processing method according to claim 10 or 11, wherein the image processing method is different from a type of a recording medium on which patches are recorded at the second time using ink. The image processing method according to claim 10, wherein the first ink and the third ink are achromatic inks, and the second ink is a chromatic ink. . 14. The recording head according to claim 10, wherein the recording head ejects one of the first ink and the third ink according to a type of the selected recording medium. The image processing method as described.

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